The present invention is directed to a child-resistant closure designed to require less torque for removal by an adult without sacrificing the child resistance safety feature incorporated into the closure.
Specifically, the inventive child-resistant closure device of the present invention includes an inner cap having a top and a cylindrical skirt depending from the top. The cylindrical skirt has both an outer surface and inner surface, with the inner surface of the skirt being threaded for threading engagement with the container when the inner cap is rotated in one direction. Conversely, the inner cap is disengageable from the container when the inner cap is rotated in an opposite direction. The outer cap is also provided with a top and a cylindrical skirt coaxial with and surrounding the skirt of the inner cap. The cylindrical skirt has an outer and inner surface with the inner and outer caps being in close confronting relation as well as being axially movable relative to one another.
Additionally, the inner surface of the skirt of the outer cap is provided with a plurality of knurlings which extend in an angular direction from the top of the outer cap. As well, the outer surface of the skirt of the inner cap is provided with a radial shoulder which is spaced dependingly downward from the top and which extends outwardly from the skirt of the inner cap. The radial shoulder is provided with a plurality of triangular saw toothed projections complimentary to the plurality of knurlings so that when the outer cap is turned in one direction, the plurality of knurlings and the plurality of triangular saw tooth projections will meet to cam the outer cap relative to the inner cap to rotate the inner cap in one direction thereby threadedly engaging the inner cap to the container. When the outer cap is rotated in an opposite direction, the plurality of knurlings will ratchet over the plurality of triangular saw tooth projections so that the rotation of the inner cap in the opposite direction to open the container is prevented. By applying an axial force to the outer cap and toward the inner cap, this enables the outer cap to impart rotation to the inner cap in the opposite direction. Accordingly, by applying this axial force, the ratcheting of the outer cap axially away from the inner cap is thereby prevented. Thus, a child-resistant screw-on closure, which, requires less torque for the removal of the closure device while still retaining the child-resistant safety feature is provided.
Child-resistant closures having relatively rotatable inner and outer components are known. However, prior art structures and arrangements have suffered from a variety of drawbacks and deficiencies. Typically, the inner component is adapted to be threaded onto and off the container with the outer component being constructed and arranged so that the two components must be manipulated in a particular fashion in order to remove the closure rather than merely rotating the part that is grasped. As such, two manipulations are required to remove the closure, i.e., the outer component must first be pushed down toward the inner component prior to rotating it in order to effect opening of the container for access to the contents. Although studies have proven this dual manipulation to be the most difficult for a child to execute in order to successfully remove the closure without special instructions, this safety locking feature becomes an annoyance to other members of the household. The elderly, in particular, often find the manipulations required to open the container bothersome.
Additionally, Kinsley U.S. Pat. No. 4,364,484 discloses a two piece child resistant closure formed from an integrally molded assembly. The integrally molded closure portion is connected to a collar portion by a web. The collar portion defines a recess to receive a closure clutch ring having a greater diameter than the recess defining portions of the collar portion thereby retaining the closure and collar portions in assembled relationship. The clutch ring defines teeth on its upper surface and the collar portions define complimentary downwardly forcing teeth. This child-resistant closure, however, does not provide a two-piece child-resistant screw-on closure having an inner cap and an outer cap, with the outer surface of the inner cap being provided with a saw toothed radial shoulder spaced dependingly downward from the top.
Scuderi U.S. Pat. No. 3,946,890 discloses a child-proof closure for containers having a threaded neck. A screw type cap is provided with a first set of teeth mounted on its side, with the teeth being set at an angle to the axis of the cap. A drive member is loosely mounted on the cap for limited axial motion. A second set of teeth is mounted on the drive member, the teeth being angled in the same direction as the first set of teeth. When the drive member is turned in the direction to remove the cap, the interaction of the teeth lifts the drive member relative to the cap so that the first and second sets of teeth disengage. Accordingly, the cap cannot be removed solely by turning. However, this arrangement does not provide the most efficient and effective construction, as this closure device requires a high degree of torque for its removal from the container neck.
None of the prior art teaches or suggests a child-resistant closure for use with a container having the outer surface of the skirt of the inner cap being provided with a radial shoulder spaced dependingly downward from the top and extending outwardly from the skirt of the inner cap. Moreover, no other prior art reference discloses such an inner cap having a radial shoulder being provided with a plurality of triangular saw tooth projections complimentary to the plurality of knurlings so that when the outer cap is turned in one direction, the plurality of knurlings and the plurality of triangular saw tooth projections will meet to cam the outer cap relative to the inner cap to rotate the inner cap in one direction to threadingly engage the inner cap on the container.
It is, therefore, an object of the present invention to provide a child-resistant closure that require less torque for its removal from a container by an adult, particularly, an elderly adult.
Another object of the invention is to provide an child-resistant closure that will be difficult for removal by a child.
A further object of the invention is to provide such a child-resistant closure having knurlings on the outer cap for engagement with corresponding projections on the inner cap to permit disengagement of the closure from the container.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.